Magnetic field behavior of small sputtered step-edge junctions

YBa2Cu3O7 step-edge junctions with widths down to 0.5 μm are fabricated on SrTiO3 substrates by Ar ion-beam milling of the steps, high-pressure on-axis magnetron sputtering, electron beam patterning and ion-beam etching of the microbridge. For ratios of film thickness to step height of ∼1/2 the curr...

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Bibliographic Details
Published in:Applied physics letters Vol. 68; no. 25; pp. 3623 - 3625
Main Authors: Vaupel, M., Ockenfuss, G., Wördenweber, R.
Format: Journal Article
Language:English
Published: 17-06-1996
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Summary:YBa2Cu3O7 step-edge junctions with widths down to 0.5 μm are fabricated on SrTiO3 substrates by Ar ion-beam milling of the steps, high-pressure on-axis magnetron sputtering, electron beam patterning and ion-beam etching of the microbridge. For ratios of film thickness to step height of ∼1/2 the current-voltage characteristics show Shapiro steps under microwave irradiation and resistively shunted junction like behavior. The periodic dependence of the critical current upon the magnetic field resembles a Fraunhofer pattern. The period of the current variation ΔB0 depends upon the width w of the junction according to the theoretical prediction for planar thin Josephson junctions: ΔB0=1.84φ0/w2. Junctions with widths of 0.7 μm possess a large magnetic field stability with ΔB0≊100 G. Small junctions (w<1 μm) exhibit voltage jumps in the Fraunhofer pattern, which are explained by flux penetration of single vortices into the electrodes.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.115750